1. Field of the Invention
The present invention relates to a stage apparatus suitable for accomplishing accurate positioning. More particularly, the invention relates to a stage apparatus used in a semiconductor exposure apparatus for mounting a wafer or the like. The present invention falls under the technical field of an exposure apparatus using such a stage apparatus, and a device manufacturing method for manufacturing a device, such as a semiconductor device, using this exposure apparatus.
2.Description of the Related Art
FIG. 14 schematically illustrates a conventional exposure apparatus.
A main body supporting member 66 is supported via a vibration removing mechanism 62 on a floor 68. A base 61 is secured to the lower half of the main body supporting member 66, and a wafer stage 60 movable in two-dimensional directions (e.g., X and Y directions) is supported on the base 61. A projection optical system 65, an interferometer reference 67 for measuring the position of the wafer stage 60, and a reticle 64, serving as an original, are provided on the upper half of the main body supporting member 66. Further, an illuminating system 63, supplying exposing light, is provided above the reticle 64.
In the aforementioned configuration, the wafer stage 60 receives a wafer supplied by a wafer transport system (not shown), a target position relative to the reticle 64 is converted by an alignment system (not shown) into interferometer data, the wafer stage 60 is moved to a prescribed position by an XY driving mechanism (not shown) with this interferometer data being a target, a reticle image is printed, and the wafer stage 60 is caused to move to the next position. The reticle image is printed onto the entire wafer by repeating these steps.
In order to improve the productivity of the exposure apparatus, it is necessary to reduce the moving time of the stage, and the exposure time. A reduction of the moving time of the stage requires an increase in the acceleration or deceleration upon movement. In order to increase the productivity of post-processing processes, the wafer diameter must be increased, and along with this, the mass of the wafer chuck and that of the wafer stage are only increasing.
Since the driving mechanism of the wafer stage 60 requires a thrust equal to the product (multiplication) of the mass of the wafer stage and the acceleration, a very large thrust produced by the driving mechanism is required under the synergistic effects of the wafer size and the acceleration. As a result, when driving the stage 60, a large reaction force is produced, causing deformation of the exposure apparatus main body, and bringing about a deterioration in the positional accuracy of the exposure and transfer, as well as deflection of the transfer pattern. As a measure against this, a reaction force receiving apparatus (such as that disclosed in Japanese Patent Laid-Open No. 6-163353 and in No. 9-4677) has been proposed.
FIG. 15 schematically illustrates a conventional reaction force receiving apparatus.
In FIG. 15, reference numeral 51 represents a reticle stage carrying a reticle; 52 a base supporting a stage; 53A and 53B anti-vibration springs for supporting the base to reduce vibration from a floor 68; 54 a stand fixed to the floor 68; and 55 a reaction force receiving member. An actuator 56 is formed by a stator 57 fixed to the base and a rotor 58 provided on the reaction force receiving member 55, and actuator 56 can produce a thrust.
FIG. 16 illustrates forces acting on the apparatus shown in FIG. 15.
In the configuration shown in FIG. 16, when the actuator 56 is not operated, a motion of the stage 51 having a mass m by the action of an acceleration a causes a reaction force ma to act on the base 52. The reaction force ma causes deformation of the main body and displacement of the anti-vibration springs 53A and 53B, resulting in fluctuation of the base 52. To prevent such deformation or fluctuation, the reaction force receiving member 55, arranged independently of the base 52, imparts a force f via the actuator 56 to offset the reaction force ma.
In a conventional reaction force receiving apparatus, however, transfer of a reaction force to the surface of the floor 68 is inevitable. As shown in FIG. 16, a plane interval force ma and a moment force M=Lma act on the floor surface, where L is a distance between the position of the center of gravity of the moving stage and the floor surface.
In general, the surface exhibits a large rigidity against the plane interval force. However, because it has a low rigidity against a moment force, floor vibration is caused by the above-mentioned moment force m=Lma. There is, therefore, a problem to be solved in that the floor vibration exerts an adverse effect on operations of the apparatus itself or on peripheral devices.
An object of the present invention is to reduce a translational force of a reaction and a moment force produced upon accelerating or decelerating the movement of a stage.
The stage apparatus of the invention for achieving the aforementioned object is provided with a movable stage, a base, having a reference plane, supporting the stage, a driving mechanism driving the stage, and a rotor acting on the stage and producing a moment so as to reduce a reaction force produced along with movement of the stage.
An exposure apparatus of the invention is provided with a stage apparatus comprising (i) a movable stage, (ii) a base, having a reference plane, supporting the stage, (iii) a driving mechanism driving the stage and (iv) a rotor acting on the stage and producing a moment so as to reduce a reaction force produced along with movement of the stage, and a light source producing exposure light for exposing a wafer via a reticle.
A device manufacturing method of the invention comprises the steps of providing an exposure apparatus including a stage apparatus comprising (i) a movable stage, (ii) a base, having a reference plane, supporting the stage, (iii) a driving mechanism driving the stage and (iv) a rotor producing a moment so as to reduce a reaction force produced along with movement of the stage, and transferring a pattern formed on a reticle onto a wafer, by the use of the exposure apparatus.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.